1. Field of the Invention
This invention pertains generally to a superhydrophobic textile, and more particularly to a micropatterned superhydrophobic textile for biofluidic transport.
2. Description of Related Art
Microfluidics has gained increasing popularity in the handling, transporting, and analyzing of minute volumes of biological and chemical fluids. Open-surface and interfacial microfluidics, where one or more gas-liquid interfaces exist as a boundary condition, are emerging directions in microfluidics from which several new and flexible operations have been established, including self-propelled motion, three-dimensional connectivity, open sample accessibility, direct reactivity and readability, in addition to conventional microflow manipulations. Specifically, paper-based testing strips, employing the capillarity force (also known as wicking force) generated by the microscopic fibrous/porous structures within the substrate, have been considered as the early historic implementation of interfacial microfluidics which are widely used in pH value indication and pregnancy testing.
The latest development of the concept of lab-on-a-paper has enabled biochemical assaying on multilayer micropatterned paper substrates fabricated by a simple printing process that form three-dimensional flow networks for multiplexed biochemical analyses (e.g., glucose, urine, and pH). In conjunction with conductive ink printing, this group has also successfully demonstrated quantitative electrochemical analysis on the paper-based devices by measuring the concentrations of heavy metal ions and glucose molecules.
More recently, the interfacial microfluidic concept has been extended to textile-based structures and surfaces (e.g., yarns and fabrics). Textile-based microfluidics utilize a similar wicking force as seen in paper that is produced by hydrophilic yarns (e.g., cotton yarns) to direct biological reagents along the fibrous structure which affords the aforementioned operational capacities of interfacial microfluidics while providing a low-cost and scalable solution based on well-established, traditional textile manufacturing techniques such as automatic weaving, knotting, and stitching. In particular, basic microfluidic functions, including pumping, mixing, separation, and networking, have been recently demonstrated on knotted yarn structures. Although the current development of capillarity-enabled interfacial microfluidics holds great promise to biofluidic manipulation, its intrinsically driven mechanism continues to be a major challenge for continuous and facilitated biofluidic transport. For instance, an external fluidic driver (e.g., capillary or syringe pumps) still remains necessary to provide continuous flow on the fabric network.
Competitive fabrics, featuring quick drying, such as CoolMax, utilize polyester fibers with irregular cross-sections to wick liquid from the surface of human skin and to spread the liquid to enhance evaporation. The only driving force is still capillary force, which diminishes when lots of liquid wets the surface. Once the textile is wetted with sweat, the gas permeability decreases and the weight increases. Moreover, the evaporation of the sweat is highly affected by the environmental humidity.